One alternative that people use to stair tread rugs are carpet runners. The difference is that a runner is a long piece of carpet that adheres to both the tread and the rise (the vertical part) of the stairs, while the tread rugs are individual rugs that attach only to the tread (the horizontal part).
There are two advantages to using carpet runners. First, they have a particular look that can be very attractive. Rather than just decorating the treads, the whole set of steps can have a unique and beautiful look. Additionally, they can protect the risers, which are the back part of the steps that go vertically. Those can frequently become scuffed from the toe of people’s shoes hitting it.
That being said, there are some significant disadvantages to carpet runners for stairs. The first is that they are very difficult to install yourself. Even with a professional installer, some models are so stiff that bending them around each step is very tough. And having carpet on the stairs that is not firmly secured is a serious safety hazard. Also, because of the material that many of them are made of, there is a strong odor that comes with the carpet runners.
Also, if there was ever a problem with stair tread rugs, you can replace one individually, instead of having to replace the entire carpet runner.Sarah - Information about stair tread rugs from http://stairtreadrugs.net